Many parallel applications suffer from latent performance limitations that may prevent them from utilizing resources efficiently while scaling to larger parallelism. Often, such scalability bugs manifest themselves only when an attempt to scale the code is actually being made---a point where remediation can be difficult. However, creating analytical performance models that would allow such issues to be pinpointed earlier is so laborious that application developers attempt it at most for a few selected kernels, running the risk of missing harmful bottlenecks. We discuss how to generate performance models for program scalability to identify scaling bugs early and automatically. We then briefly discuss key limitations of our first approach and show various techniques how to remedy them and enable efficient multi-parameter modeling that can be employed for hardware/software co-design. This talk will summarize the key results from papers presented at SC'13, SPAA'14, and PACT'14 and outline several new research challenges.

Bio

Torsten is an Assistant Professor of Computer Science at ETH Zürich, Switzerland. Before joining ETH, he lead the performance modeling and simulation efforts of parallel petascale applications for the NSF-funded Blue Waters project at NCSA/UIUC. He is also a key member of the Message Passing Interface (MPI) Forum where he chairs the "Collective Operations and Topologies" working group. Torsten won best paper awards at the ACM/IEEE Supercomputing Conference 2010 (SC10), EuroMPI 2013, ACM/IEEE Supercomputing Conference 2013 (SC13), and other conferences. He published numerous peer-reviewed scientific conference and journal articles and authored chapters of the MPI-2.2 and MPI-3.0 standards. For his work, Torsten received the SIAM SIAG/Supercomputing Junior Scientist Prize in 2012 and the IEEE TCSC Young Achievers in Scalable Computing Award in 2013. Following his Ph.D., the received the Young Alumni Award 2014 from Indiana University. Torsten was elected into the first steer ing committee of ACM's SIGHPC in 2013. He was the first European to receive those honors. In addition, he received the Best Student Award 2005 of the Chemnitz University of Technology. His research interests revolve around the central topic of "Performance-centric Software Development" and include scalable networks, parallel programming techniques, and performance modeling. Additional information about Torsten can be found on his homepage at htor.inf.ethz.ch.